Disclosed are a float bath and a float manufacturing process enabling to shape a glass with a high forming temperature without shortening the life of a strap for feeding power to a heater. A float bath (10) comprises a bottom unit (12) holding a molten tin (11) and a roof unit (14) covering the bottom unit (12). The space inside the roof unit (14) is divided by a roof brick layer (16) into an upper space (20) and a lower space (21). A heater (18) is so arranged as to pass through a through hole (17) which is formed in the roof brick layer (16). The thickness of the roof brick layer (16) is not less than 320 mm.